Note 3 - Acquisitions (Detail) (USD $)	3 Months Ended		6 Months Ended				3 Months Ended	6 Months Ended	12 Months Ended		3 Months Ended	6 Months Ended	12 Months Ended	3 Months Ended	6 Months Ended		12 Months Ended				3 Months Ended		6 Months Ended	3 Months Ended	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011 Accrued [Member] MES Group [Member]	Dec. 31, 2011 Accrued [Member] Other 2011 Acquisitions [Member]	Jun. 30, 2011 MES Group [Member]	Jun. 30, 2011 MES Group [Member]	Dec. 31, 2011 MES Group [Member]	Feb. 28, 2011 MES Group [Member]	Jun. 30, 2011 Premex Group [Member]	Jun. 30, 2011 Premex Group [Member]	Dec. 31, 2011 Premex Group [Member]	Jun. 30, 2011 Other 2011 Acquisitions [Member]	Jun. 30, 2012 Other 2011 Acquisitions [Member]	Jun. 30, 2011 Other 2011 Acquisitions [Member]	Dec. 31, 2011 Other 2011 Acquisitions [Member]	Dec. 31, 2010 Other 2011 Acquisitions [Member]	Feb. 18, 2011 National IME Centres Inc. [Member]	Sep. 28, 2011 MLS Group of Companies Inc. [Member]	Jun. 30, 2011 Additional Interest Expense [Member]	Jun. 30, 2011 Incremental Depreciation [Member]	Jun. 30, 2011 Incremental Depreciation [Member]	Jun. 30, 2011 Selling, General and Administrative Expenses [Member]	Jun. 30, 2011 Selling, General and Administrative Expenses [Member]
Business Acquisition, Percentage of Voting Interests Acquired									100.00%				100.00%						100.00%	100.00%
Business Acquisition, Cost of Acquired Entity, Purchase Price									$ 215,000,000				$ 108,400,000				$ 44,600,000
Business Acquisition, Cost of Acquired Entity, Cash Paid									175,000,000				66,500,000				43,200,000
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares (in Shares)									1,424,501				661,610				214,926
Business Acquisition, Equity Interest Issued or Issuable, Value Assigned									30,000,000				15,100,000				2,000,000
Closing Price Per Share (in Dollars per share)										$ 21.07			$ 22.85
Business Acquisition, Purchase Price Allocation, Liabilities Assumed										10,000,000			26,800,000
Business Acquisition, Cost of Acquired Entity, Transaction Costs					2,000,000	639,000							646,000				106,000	102,000
Business Combination, Separately Recognized Transactions, Additional Disclosures, Acquisition Cost Expensed	14,000		35,000				82,000	521,000			615,000	643,000
Business Acquisition, Purchase Price Allocation, Current Assets, Cash and Cash Equivalents																	564,000
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Consideration Transferred															1,500,000
Business Acquisition, Purchase Price Allocation, Goodwill, Expected Tax Deductible Amount															18,300,000
Business Acquisition Purchase Price Allocation Intangible Assets Expected Tax Deductible Amount															20,800,000
Business Acquisition, Pro Forma Revenue														126,900,000		248,100,000
Business Acquisition, Pro Forma Net Income (Loss)		993,000		836,000
Business Acquisition, Pro Forma Earnings Per Share, Basic And Diluted (in Dollars per share)		$ 0.03		$ 0.02
Business Acquisition Proforma Adjustments				$ 4,600,000																	$ 1,300,000	$ 2,600,000	$ 8,400,000	$ 4,700,000	$ 9,900,000